During high-frequency communication, adoption of a higher carrier frequency for transmission may cause average path loss much higher than that of a conventional Long Term Evolution (LTE) system. An LTE system is needed to have area coverage which maximally reaches 100 km. If the maximum coverage is reached, the area coverage of high-frequency communication may maximally reach 1 km if only average path loss is considered. However, if high air absorption, sensitivity to shadow fading and other features of an actual high-frequency carrier are considered, actually supported coverage is smaller than 1 km. If high-frequency communication supports maximum coverage of 1 km, a Signal to Interference plus Noise Radio (SINR) different from that of an LTE system may be obtained within the same coverage area, and a signal to noise ratio of the former is at least 20 dB lower than that of the latter. In order to ensure that high-frequency communication and the LTE system have an approximate SINR within the same coverage, it is needed to ensure accommodation of more antennae per unit area.
Accommodation of more antennae means that beamforming may be adopted to ensure coverage of high-frequency communication. From an early design concept of LTE, it is needed to accurately obtain channel state information to obtain a beamforming weight from the channel state information, thereby achieving a good beamforming effect. In order to obtain a better beamforming weight, for a base station on a sending end, a terminal on a receiving end is needed to feed back downlink channel state information or a weight; while for the receiving end, the base station on the sending end is needed to feed back uplink channel state information or a weight, so that it is guaranteed that the base station may send a downlink service using an optimal beam and the terminal may also send an uplink service using an optimal beam. The base station cannot cover the receiving end by virtue of the optimal beam before obtaining the weight, so that a reference signal sent by the base station cannot be measured by the receiving end; or even though the base station covers the terminal, the terminal cannot achieve the same coverage as the base station, and a fed-back content cannot be acquired by the base station, so that selection of a beamforming weight and normal communication are also impossible.